What is a chordate? How are vertebrates different from chordates?
Chordate’s are animals that have very specific characteristics. They have a structure called a Notochord which consists of a hollow nerve cord on the back, pharyngeal clefs, and a muscular tail. They probably sound like a lot of creatures you already know! In fact, we are Chordates! Embryo’s have a little tail when they are being created but it is absorbed and becomes the tail bone. The Notochord is a long flexible rod between the digestive tract and the hollow nerve cord. The hollow nerve cord is actually a dorsal fin! Most chordates have Pharyngeal Clefts. These are like little patches that are on the sides of the Pharynx (the area behind the head/neck and behind the mouth). These develop into gills for aquatic animals and into ears and a neck and head for land animals.
Vertebrates have very extensive skulls, and by extensive I mean very complex. Their backbones are made of vertebrae. The classification of different Vertebrates are largely based on the skull and backbone of the creature. Like Gnathostomes, which are vertebrates with hard jaws. Or Tetrapods, which are Vertebrates with four limbs or “four feet”.
Despite the differences between these two different categories of creatures, they have many things in common. All Vertebrates are Craniates and all Craniates are Chordates and all Chordates are animals!
Biology R. Lesson, 110